HIGH DOSES OF RECOMBINANT HUMAN ERYTHROPOIETIN FAIL TO ACCELERATE PLATELET RECONSTITUTION IN ALLOGENEIC BONE MARROW TRANSPLANTATION. RESULTS OF A PILOT STUDY

BACKGROUND AND OBJECTIVE: The effectiveness of recombinant human erythropoietin (rhEpo) in accelerating erythroid engraftment in patients undergoing allogeneic bone marrow transplantation (BMT) has been demonstrated in previous studies. On the other hand, there are experimental data suggesting that high doses of rhEpo might also exert a stimulatory effect on thrombopoiesis. METHODS: We carried out a pilot study on the use of high doses of rhEpo (500 U/kg/day for 30 days after transplant) in ten patients (HD-Epo group) receiving BMT to evaluate the effects on both erythroid and platelet (Plt) engrafment. This group was compared to ten BMT patients who had not received the hormone (Placebo group). RESULTS: The HD-Epo group patients showed signs of accelerated erythropoietic recovery; in fact, the time required to reach a reticulocyte count higher than 30 x 10(9)/L was significantly shorter than in the Placebo group, while the number of high RNA content reticulocytes (HFR) was about three times greater. Circulating transferrin receptor (TfR) levels 30 days after BMT were also significantly higher in the HD-Epo group than in the other. Finally, the number of red blood cell (RBC) transfusions in the first 30 days following BMT was about twofold lower in the HD-Epo group; moreover, 4/10 patients who were treated with HD-Epo did not require any RBC units. No significant effects on the engraftment of platelets or on the number of Plt transfusions were observed in the HD-Epo as compared to the Placebo group. No adverse effect was noted on granulocytopoiesis, nor were any adverse clinical experiences found in patients who had been treated with erythropoietin at high dosages. INTERPRETATION AND CONCLUSIONS: These data confirm that rhEpo may stimulate erythroid reconstitution after BMT, while its effects on Plt engraftment and on Plt transfusion requirements are minimal.